During fabric knitting operation of a conventional circular knitting machine, feeding yarns have to be stretched tightly to enhance smooth of the knitting operation. The yarns have to go through various types of motions such as removing, guiding and feeding that incur friction with yarn guiding blades or yarn feeding plates and generate a lot of loose floss. As knitting elements of the circular knitting machine are automatically and regularly sprayed with lubricant or coolant during knitting operation, the fast spinning needle cylinder tends to hit the lubricant or coolant to generate foam type oil sludge adhered to the yarn feeding plates. The dropping floss easily adheres to the smeared yarn feeding plates. If the oil sludge is not cleared regularly, the floss accumulates to become cotton balls to hinder forward operation of the yarns, or even be carried with the yarns to be knitted to become the fabric, and the fabric is formed uneven bulged spots and defects thereon that severely affect fabric quality.
There are many floss blowing techniques disclosed in the prior arts. References can be found in Japan patent No. 2000-239951, Japan patent No. 3352726 and U.S. Pat. No. 7,017,375B1. Japan patent No. 2000-239951 (called the first conventional technique hereinafter) discloses a floss blowing technique (referring to FIG. 4) which blows floss accumulated in yarn guiding apertures of yarn guiding blades on one side from up to down, but does not blow the floss on the vertical yarn feeding plates. Japan patent No. 3352726 (called the second conventional technique hereinafter) discloses another floss blowing technique (referring to FIGS. 1 and 6) which provides a mechanism turning means to blow floss accumulated in the yarn guiding apertures of the yarn guiding blades in a greater range on one side from up to down. It also adopts the same mechanism turning means to blow the floss on yarn feeding plates in a greater range on one side from inner side to outer side, but does not blow the floss on the vertical yarn feeding plates from the outer side towards the inner side. U.S. Pat. No. 7,017,375B1 (called the third conventional technique hereinafter) discloses yet another floss blowing technique (referring to FIGS. 4A and 6) which provides a hose to swingingly blow floss accumulated in the yarn guiding apertures of the yarn guiding blades in a greater range on one side from up to down. It also adopts the same hose to swingingly blow the floss on the yarn feeding plates in a greater range on one side from inner side to outer side, but also does not blow the floss on the vertical yarn feeding plates from the outer side towards the inner side. Moreover, all of the aforesaid three conventional techniques mainly aim to blow the floss from the yarn guiding apertures of the yarn guiding blades. In practice, the floss is most likely to accumulate around the yarn feeding apertures at the outer lower half portion of the yarn feeding plates, namely the final distal end where the yarn is picked up by a knitting needle before knitting the fabric, that causes the floss to be carried with the yarn for knitting and affects the fabric quality. All the aforesaid three conventional techniques, due to their structural and design constraints, do not provide direct floss blowing structure or function to target the outer lower half portion of the yarn feeding plates from outside towards inside. Hence they fail to target the outer lower half portion of the yarn feeding plates where the floss is most likely to be accumulated to provide most direct floss blowing at the shortest distance from the outside towards the inside. In other words, the floss at the final distal end where the yarn is picked up by the knitting needle before knitting the fabric is not blown away. As a result, the accumulated floss often is carried with the yarn picked up by the knitting needle for knitting fabric and creates detects of uneven bulged spots on the fabric that severely affect the fabric quality.